We come across this both with respect to proponents and within government.
When we say “serious harm to fish”, for example, if we had a population of short-nosed sturgeon that had 25 fish in it, and there were five adult females, losing one adult female would be an important loss. It would be serious harm. Conversely, if we had a population of 100,000 hammer handle pike, northern pike—they're about 10 inches long—losing potentially 1,000 of those fish might not have a serious impact on the population.
When you say “death of fish”, and you say, “this is serious harm”, is that “death of fish” for one fish or to a proportion of the population, as I've said? there's that question as to what is the exact level of serious harm. In some respects, it doesn't have a qualifier that might say “this is some particular level that might be important”.